Saddle
Developer:
Meca Enterprises
Chris Rosencutter
chris@mecaconsulting.com
Description:
Perform analysis of a horizontal vessel supported on two saddles.
The program performs a complete analysis of teh vessels based
upon L. P. Zick's analysis procedure. The program allows the user
to specify the wind load, thermal loads, liquid load, and seismic
loads on the vessel. A complete analysis is also performed on the
saddle, calculating stresses on bolts, base plate, web, stiffeners, and
wear plate.
Platform:
Saddle is a Microsoft Excel spreadsheet. It requires MS Excel
2000 or later to run.
Units:
English or Metric
(Click of the button automatically toggles all inputs and results)
Sample Output:
The following pages are the output from the Saddle spreadsheet.
As an example, we have simulated an example of the Zick analysis
performed in the “Pressure Vessel Handbook” by Megyesy. The
example in Megyesy does not address the design of the saddle
itself, so there is only a comparison of the vessel stresses.
In the output you will see a note symbol that looks like this Æ
If you double click this note, you will receive further explanation
of the output.
Purchase:
You may purchase this program at www.mecaconsulting.com .
Saddle v1-1
per "Pressure Vessel Design Manual" by Dennis R. Moss
Customer: Meca
Desc: Example from Pressure Vessel Handbook
H
Project: Pg 93
by: CR
H
L
B
Fixed Saddle
A
OD
ts
P
Pe
L
H
A
B
HType
th
V
I
Exp
Z
I
Sc
Tinst
Tmin
Tmax
u
fc
S
Fys
Fy
Emod
Fbolt
Fvbolt
Av
JE
W
Sliding Saddle
Ls
Vessel Information
Outside Diameter of Vessel
Corroded Thickness of Shell
Internal Design Pressure
External Design Pressure
Tangent to Tangent Length of Vessel
Depth of Head
Distance from Head Tangent to Saddle Center Line
Height from vessel centerline to bottom of saddle
Head Type
Corroded Thickness of Head
Wind Design (ASCE 7-98)
Design Wind Speed
Importance Factor
Exposure
Seismic Design (UBC 1997)
UBC 1997 Seismic Zone
Importance Factor
Soil Coefficient (SA, SB, SC, SD, or SE)
Temperature
Installation Temperature of Vessel
Minimum Temperature of Vessel
Maximum Temperture of Vessel
Coefficient of Friction between Saddle and Concrete
Allowable bearing pressure on concrete
Material Properties
Allowable Stress: Vessel Shell
Yield Stress of Shell at Design Temperature
Yield Stress of Saddle
Modulus of Elasticity of Saddle
Allowable Tensile Stress on Bolts
Allowable Shear Stress on Bolts
Coefficient of Thermal Expansion of Vessel
Joint Efficiency
Weight
Total Weight (If zero, program will estimate)
A
120.0000
1.0000
250.00
0.00
960.00
21
48.00
69.00
Hemis
1
in
in
psig
psig
in
in
in
in
in
0 mph
1
C
0
1
SC
70.00
70.00
70.00
0.45
750
Deg. F
Deg. F
Deg. F
17,500
38,000
36,000
2.900E+07
20,000
10,000
7.00E-06
0.85
psi
psi
psi
psi
psi
psi
in/in/F
psi
600,000 lbs
Saddle v1-1
per "Pressure Vessel Design Manual" by Dennis R. Moss
Customer: Meca
Desc: Example from Pressure Vessel Handbook
Project: Pg 93
by: CR
wp
wb
tw
Theta
Lh
B
d1
d1
tb
Lrib
E
F
wb
d1
tb
wp
Lh
tw
F
E
Saddle Information (Note Click "Std Dims" button to get a standard saddle)
Width of Saddle perpendicular to Longitudinal Axis
Theta =
120.15
104.000
Width of Saddle at Bottom (along Longitudinal Vessel Axis)
9.000
Width of Saddle at Top of Saddle (along longitudinal Vessel axis)
24.000
Distance from Outside of Baseplate to First Rib
0.000
Thickness of Base Plate
1.000
Width of wear plate
24.000
Wear Plt ext. above Horn
1.000
Thickness of Wear Plate
0.750
Nr Ribs
Spaced
Evenly
Toward Fixed Saddle
Yc
Ye
J
d1
tw
Sliding Saddle
Bolt shown in cold
as-installed Position
d2
Lb
tweb
J
Nr
Nb
Dbolt
Ww
d2
in
in
in
in
in
in
in
in
F
Saddle Information
Distance from Outside of Baseplate to First Rib
Center to Center bolt spacing in transverse direction
Thickness of Web
Thickness of Ribs
Number of Ribs
Number of Anchor Bolts per Saddle
Nominal Diameter of Bolt
Fillet Leg Size (Web to Baseplate)
Lb
0.000
80.000
0.75
0.75
2
2
1.250
0.750
in
in
in
in
in
in
Saddle v1-1
per "Pressure Vessel Design Manual" by Dennis R. Moss
Customer: Meca
Desc: Example from Pressure Vessel Handbook
Project: Pg 93
by: CR
Calculated Parameters
Rm
Rs
Ls
Theta
ThetaW
Mean Radius of Shell
Radius of Shell
Saddle Spacing: L-2*A
Saddle Angle: 2*Atan((E-2*d1)/OD)
Angle of Wear Plate
Wtot
User Entered Total Weight
59.500
60.000
864.000
120.1
122.1
in
in
in
Deg
Deg
Calculate Weights
De
zg
Alpha
Kz
Cf
Gq
qz
Afl
Flw
Aft
Ftw
Ca
V
Fls
Fts
Ye
Yc
Flt
Fl
Ft
Qo
Q1
Q2
Q
Wind Loading: (Based upon ASCE 7-98)
Effective Diameter based upon Table 3-24
Constant from table 6-4
Constant from table 6-4
2.01*((B+OD/2)/zg)^(2/Alpha)
Shape Factor
Gust Factor (Rigid Structure)
Wind Pressure: 0.00256*Kz*V^2*I
PI()*(De/12)^2/4
Af*Cf*Gq*qz
De*(L+2*H)/144
(Aft*Cf*Gq*qz)*0.5
Seismic Loading: (Based upon UBC)
Seismic Coefficient based upon Soil and Zone
2.5*Ca*I*W / R
V / 1.4
V / (2 * 1.4)
Thermal Expansion
Maximum Expansion of Vessel
Maximum Contraction of Vessel
Frictional Force due to Expansion/Contraction (u*Wtot/2)
Saddle Reactions
Maximum Longitudinal Force: Max(Flw, Fls, Flt, Flp)
Maximum Transverse Force: Max(Ftw, Fts)
Operating Load on Saddles: (Wtot)/2
Reaction due to Long Force: Wo/2+Fl*B/Ls
Reaction due to Tran Force: Wo/2+3*Ft*B/E
Maximum of Q1 or Q2
600,000 lbs
141.6000
900.0000
9.5000
1.3353
0.8
0.85
0.00
109
985
-
in
psf
ft^2
lbs
ft^2
lbs
0.0000
lbs
lbs
lbs
300,000
300,000
300,000
300,000
in
in
lbs
lbs
lbs
lbs
lbs
lbs
lbs
Saddle v1-1
per "Pressure Vessel Design Manual" by Dennis R. Moss
Customer: Meca
Desc: Example from Pressure Vessel Handbook
A./Rs
K1
K2
K3
K4
M1
M2
S1
S2
S4
S6
Check # 1
Check # 2
Check # 3
tes
tes1
tes2
S9
S10
S11
S12
fx
fp
Element
Shell
Wear Plt
Web
Baseplt
c1
c2
Is
As
Beta
K1
fh
ft
d
M
fb
fb
Ab
Bp
fbplt
Project: Pg 93
by: CR
"K" Constants from Figure 3-46
K5
=
K6
=
K7
=
K8
=
K9
=
Longitudinal Bending
6*Q*(8*A*H+6*A^2-3*Rm^2+3*H^2)/(3*L+4*H)
3*Q*((3*L^2+6*Rm^2-6*H^2-12*A*L-16*A*H)/(3*L+4*H))
Long. Bending @ Saddles w/o Stiffeners - Tension: M1/(K1*Rm^2*ts)
Long. Bending @ Saddle w/o Stiffeners - Compression: -M1/(K7*Rm^2*ts)
Long. Bending @ Midspan: +/- M2/(pi()*Rm^2*ts)
Tangential Shear
Tang. Shear - shell not stiffened A>0.5R: (K2*Q/(Rm*ts))*((L-2*A)/(L+4*H/3))
Circumferential Bending
Lh >= Rm/10:
1.00
<=
5.95
Is A <= 0.5*Rm:
48.00
>=
29.75
Wp >= wb+1.56*(Rm*ts)^0.5
24.00
<=
36.03
Check # 1 & # 2 did not both pass: ts
Check # 3 did not both pass: ts
Check # 1 & # 2 did not both pass: ts^2
Bend @ horn L>=8R: -Q/(4*ts*(wb+1.56*(Rm*ts)^0.5))-3*KK6*Q/(2*tes2)
Bend @ horn L<8R: -Q/(4*ts*(wb+1.56*(Rs*ts)^0.5))-12*KK6*Q*Rs/(L*ts^2)
Since A>0.5*Rs --> Add'l Tension in Head = 0
Circ Compression: -KK5*Q/(tes1*(wb+1.56*(Rm*tes1)^0.5))
Pressure Stresses
Longitudinal Pressure Stress
P*Rm/(2*ts)
Circumferential Pressure Stress
P*Rm/ts
Saddle Design - Web
b
h
Area
I
d
A*d
in
in
in^2
in^4
in
in^3
48.167
1.000
48.2
4.01.E+00
0.50 2.408E+01
36.084
0.750
27.1
1.27.E+00
1.38 3.721E+01
0.750
37.250
27.9
3.23.E+03
20.38 5.692E+02
9.000
1.000
9.0
7.50.E-01
39.50 3.555E+02
Area =
112.2
A*Y = 9.860E+02
Dist from Id of Shell to Center of Gravity for Saddle (A*Y/Area)
Dist from Center of Gravity to Base Plate
Moment of Inertia of Saddle
Area of Saddle
Pi() - Theta/2
(1+COS(Beta)-0.5*(SIN(Beta))^2)/(PI()-Beta+(SIN(Beta))*(COS(Beta)))
Saddle Splitting Force: K1*Q
Tensile Stress in Saddle: fh/As
B-Rs*Sin(Theta)/Theta
fh * d
Bending Stress in Saddle: M*C1/I
Saddle Design - Wear Plate
Bending Stress in Wear Plate: 6*Q*K5*wb/(8*tw^2*Rs)
Saddle Design - Baseplate
Bearing Area: E * F
Bearing Pressure: Q/Ab
(3*Q*F)/(4*E*tb^2)
=
=
=
=
=
0.8000
0.3357
1.1686
0.8775
0.4004
0.7595
0.0369
0.6041
0.3399
0.0529
6.372E+05
5.603E+07
536
-298
5,038
in-lbs
in-lbs
psi
psi
psi
5,153 psi
FALSE
FALSE
FALSE
1.0000
1.0000
1.0000
-18,694
-10,385
0
-6,323
in
in
in
psi
psi
psi
psi
7,438 psi
14,875 psi
A*d^2
in^4
1.204E+01
5.117E+01
1.160E+04
1.404E+04
I=
8.79
0.21
2.894E+04
112.2
2.093
0.2038
61,137
545
49
3.005E+06
913
Itot
in^4
1.606E+01
5.243E+01
1.483E+04
1.404E+04
2.894E+04
in
in
in^4
in^2
rads
lbs
psi
in
in-lbs
psi
17,624 psi
936 in^2
321 psi
19,471 psi
Saddle v1-1
per "Pressure Vessel Design Manual" by Dennis R. Moss
Customer: Meca
Desc: Example from Pressure Vessel Handbook
Tension?
Pb
Abolt
fal
fv
M
e
E/6
Project: Pg 93
by: CR
Saddle Design - Anchor Bolts
Longitudinal Load
Is Qo > Q1?
300,000
<
300,000
Since Q0>Q1 then Tensile Load will exist Each Bolt: ((Q1-Q0)/(Nb))
(Pi()/4) * Dbolt^2
Bolt Tensile Stress: Pb/Abolt
Shear Load (Assume Fixed Saddle takes entire load)
Shear Stress: Fl / Abolt
Transverse Load
Transverse Moment: Ft * B
M / Q0
E/6
Since e < E / 6 --> There is No Uplift
FALSE
lbs
1.23 in^2
psi
-
psi
in-lbs
in
17.333 in
Saddle v1-1
per "Pressure Vessel Design Manual" by Dennis R. Moss
Customer: Meca
Desc: Example from Pressure Vessel Handbook
Project: Pg 93
by: CR
Saddle Design - Ribs
Outside Ribs
Lrib
Lotrib
Pr
Ar
fa
I1
C1
r
L1
Lr
Cc
Fa
fu
M
fb
SR
Litrib
Pr
Ar
fa
I2
C2
r
L2
Lr
Cc
Fa
fu
M
fb
SR
Rib Spacing: (E-2*d1)/(Nr-1)
Tributary Length: Min (e , 0.5*Lrib)
Axial Load on Ribs: Bp * F * Lotrib
Area of Web and Rib: J*(F-2*d2-tweb) + tweb*(Lotrib-d1)
Compressive Stress: Pr / Ar
(J/12) * ((wb + F) / 2)^3
(wb + F) / 4
Radius of Gyration: (I1 / Ar)^0.5
Height of Saddle: B - Rs * Cos(Theta/2)
Slenderness Ratio: L1 / r
(2*PI()^2*Emod/Fy)^0.5
(1-Lr^2/(2*Cc^2))*Fy/(5/3+3*Lr/(8*Cc)-Lr^3/(8*Cc^3))
Unit Force: Fl / (2 * E)
Bending Moment: 0.5 * fu * e * L1
Bending Stress: M * C1 / I1
Stress Ratio: fa/Fa+fb/Fb
Inside Ribs
Tributary Length: Min (e , Lrib)
Axial Load on Ribs: Bp * F * Litrib
Area of Web and Rib: J*(F-2*d2-tweb) + tweb*Litrib
Compressive Stress: Pr / Ar
(J/12) * ((wb + F) / 2)^3
0.5 * Wb
Radius of Gyration: (I2 / Ar)^0.5
Height of Saddle: B - (Rs^2-(E/2-d1-Lrib)^2)^0.5
Slenderness Ratio: L1 / r
(2*PI()^2*Emod/Fy)^0.5
(1-Lr^2/(2*Cc^2))*Fy/(5/3+3*Lr/(8*Cc)-Lr^3/(8*Cc^3))
Unit Force: Fl / (2 * E)
Bending Moment: 0.5 * fu * e * L2
Bending Stress: M * C2 / I2
Stress Ratio: fa/Fa+fb/Fb
104.0000
52.0000
150,000
45.19
3,320
2.808E+02
8.250
2.493
39.067
15.7
126.1
20,853
0.000E+00
0.16
in
in
lbs
in^2
psi
in^4
in
in
in
104.000
3.000E+05
84.19
3,563
8.640E+02
12.000
3.204
39.1
12.2
126.1
21,043
0.000E+00
0.17
in
lbs
in^2
psi
in^4
in
in
in
psi
lb/ft
in-lbs
psi
psi
lb/ft
in-lbs
psi
Saddle v1-1
per "Pressure Vessel Design Manual" by Dennis R. Moss
Customer: Meca
Desc: Example from Pressure Vessel Handbook
Description
Shell not stiffened
Horn of Saddle - Shell Not Stiffened
Horn of Saddle - Shell not Stiffened
Circumferential Compressive Stress
Longitudinal Tension at Saddles
Longitudinal Bending @ Midspan
Tension in Head
Tensile Stress in Web
Bending Stress in Saddle
Bending Stress in Wear Plate
Bending stress in Baseplate
Bearing pressure on Concrete
Bending Stress
Axial Stress
S.R. for Bending + Axial
Bending Stress
Axial Stress
S.R. for Bending + Axial
Tensile Stress
Shear Stress
Stress Summary
SR
Result
Tangential Shear
S6
0.37
PASS
Circumferential Bending
S9
0.71
PASS
S10
0.40
PASS
S12
0.33
PASS
Combined Stress - Tension
S1+fx
0.54
PASS
S4+fx
0.84
PASS
S11+fp
0.80
PASS
Saddle Web
ft
0.03
PASS
fb
0.04
PASS
Saddle Wear Plate
fb
0.74
PASS
Saddle Base Plate
fbplt
0.82
PASS
Bp
0.43
PASS
Saddle - Outside Ribs
fb
0.00
PASS
fa
0.16
PASS
ftot
0.16
PASS
Saddle - Inside Ribs
fb
0.00
PASS
fa
0.17
PASS
ftot
0.17
PASS
Saddle - Inside Ribs
fa
0.00
PASS
fv
0.00
PASS
Equation
Project: Pg 93
by: CR
Actual
Allowable
5,153
14,000 psi
(18,694)
(10,385)
(6,323)
26,250 psi
26,250 psi
19,000 psi
7,974
12,475
14,875
14,875 psi
14,875 psi
18,594 psi
545
913
21,600 psi
23,760 psi
17,624
23,760 psi
19,471
321
23,760 psi
750 psi
3,320
0.16
23,760 psi
20,853 psi
1.00
3,563
0.17
23,760 psi
21,043 psi
1.00
-
20,000 psi
10,000 psi